feat: add Vite configuration for Tiku.PlatformAdmin.Web and update documentation

- Introduced Vite configuration files (vite.config.js, vite.config.ts, vite.config.d.ts) for the React frontend.
- Configured server proxy settings for API endpoints.
- Added Vitest configuration files (vitest.config.js, vitest.config.ts, vitest.config.d.ts) for testing.
- Updated architecture overview to reflect the separation of the platform admin frontend into its own React project.
- Modified quickstart documentation to guide users on starting the platform admin frontend.

Tiku.Api/Properties/launchSettings.json

@@ -7,7 +7,8 @@
       "launchBrowser": false,
       "applicationUrl": "http://localhost:5090",
       "environmentVariables": {
-        "ASPNETCORE_ENVIRONMENT": "Development"
+        "ASPNETCORE_ENVIRONMENT": "Development",
+        "ASPNETCORE_HOSTINGSTARTUPASSEMBLIES": "Microsoft.AspNetCore.SpaProxy"
       }
     },
     "https": {
@@ -16,7 +17,8 @@
       "launchBrowser": false,
       "applicationUrl": "https://localhost:7093;http://localhost:5090",
       "environmentVariables": {
-        "ASPNETCORE_ENVIRONMENT": "Development"
+        "ASPNETCORE_ENVIRONMENT": "Development",
+        "ASPNETCORE_HOSTINGSTARTUPASSEMBLIES": "Microsoft.AspNetCore.SpaProxy"
       }
     }
   }